Curl request for ASP page

A web page I am working on loads this page (http://ift.tt/1FsXpS0) into an iframe. There is a button that says "Next" in a form on the page. When the user clicks "Next" the form submits. It calls itself according to the action attribute on the form. The page that returns is step two.

I have changed the iframe so that it loads a php file which requests the same page as above with cURL. I also adjusted the form's Action attribute so that it calls a php file which does a cURL request for the page (http://ift.tt/1FsXpS0). My problem is that I am not able to get Step 2 to appear when I submit the form through the cURL request. How can I get the cURL request to submit the inputs so that step 2 will appear?

Here is the php code that I am using to make the request for the ASP page with the posted inputs from the Step 1 form.

<?php

function getUrlContent($url, $postedVarsMinus1 = NULL)
{
    //open connection - initialize cURL handler
    $ch = curl_init();

    //set fieds to be posted
    if(!is_null($postedVarsMinus1))
    {
        $fields = $postedVarsMinus1;
    }
    else
    {
        $fields = "";
    }

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_POST, true); //true

    curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

    //execute post
    $result = curl_exec($ch);

    $httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);

    $contentType = curl_getinfo($ch, CURLINFO_CONTENT_TYPE);
    curl_close($ch);

    return ($httpcode>=200 && $httpcode<300) ? array($result, $contentType) : false;
}
?>